Frequency and type of electrocardiographic abnormalities in cocaine abusers (electrocardiogram in cocaine abuse)

Electrocardiographic abnormalities of 200 asymptomatic, chronic cocaine abusers (aged ≤45 years, 69% Mack) admitted for rehabilitation (group 1) were compared with 38 cocaine abusers treated in the emergency room (group 2), 21 cocaine abusers who died suddenly (group 3), and 425 control subjects from the general population. In group 1, 39% of electrocardiograms were abnormal: Increased QRS voltage was noted in 27%, ST elevation in 22%, ST-T changes in 17%, and prior myocardial infarction in 3%. Increased QRS voltage (35% vs 10%, p = 0.00007) and ST elevation (26% vs 13%, p = 0.0278) were more prevalent in blacks than in whites. With use of Minnesota coding, electrocardiograms in group 1 were compared with those of 141 Mack and 284 white men (aged < 40 years) from the general population. ST elevation was more prevalent in both black (22% vs 8%, p = 0.00073) and white (15% vs 1%, p < 0.00001) cocaine abusers than in the general population. Compared with group 1, group 2 had higher prevalence of sinus tachycardia (16% vs 1%, p = 0.0002), supraventricular tachycardia (5% vs 0%, p = 0.024), ST-T changes (34% vs 17%, p = 0.0164), and QTc > 440 ms (26% vs 4%, p = 0.00003); mean QTc was also greater among group 2 subjects (427 ± 38 vs 404 ± 19 ms, p < 0.0001). In group 3, QTc was > 440 ms in 6 of 8 subjects (75%) with 12-lead electrocardiograms. Mean QTc was greater in group 3 (457 ± 29 ms) than in group 1 (404 ± 19 ms, p < 0.0001) and group 2 (427 ± 38 ms, p = 0.002). Electrocardiographic abnormalities are common among asymptomatic, chronic cocaine abusers, with a higher prevalence in blacks. During acute cocaine abuse, abnormalities are more prevalent and QT is prolonged.